[ti:New Study Shows Bone Loss in Space Can Be Permanent+++最新研究表明太空旅行会造成永久性骨流失]
[by:www.21voa.com]
[00:00.00]更多听力请访问21VOA.COM
[00:00.00]A recent study about bone loss in astronauts
[00:04.72]is providing important information
[00:07.43]about the effects of space travel on the human body.
[00:12.20]The research could help space agencies reduce harmful effects
[00:16.81]on astronauts in future space flights.
[00:20.44]The recent research gathered new data on bone loss in 17 astronauts
[00:27.09]who worked on the International Space station.
[00:30.80]It involved 14 male and three female astronauts.
[00:36.26]Their average age was 47 years old.
[00:40.74]The study looked at bone loss caused by the microgravity conditions,
[00:46.38]or very weak force of gravity, in space.
[00:51.01]It also studied how bone mineral density can be regained back on Earth.
[00:57.01]The astronaut's missions were about five and one half months on average.
[01:03.27]One year after returning to Earth, the astronauts had 2.1 percent
[01:10.07]reduced bone mineral density at the tibia, a bone in the leg.
[01:15.74]They also had on average a 1.3 percent reduction in strength.
[01:22.79]Nine experienced permanent loss
[01:26.57]- they did not fully recover bone mineral density after the space flight.
[01:31.98]Leigh Gabel of the University of Calgary was the lead writer
[01:38.24]of the research published recently in Scientific Reports.
[01:42.75]Gabel said that what is new about this study
[01:46.54]"is that we followed astronauts for one year
[01:50.05]after their space travel to understand if and how bone recovers."
[01:56.39]Gable noted that astronauts experienced bone loss
[02:01.25]during six-month spaceflights that one would expect to see
[02:05.72]in older people over 20 years on Earth.
[02:09.83]These astronauts "only recovered about half of that loss
[02:14.54]after one year back on Earth," she added.
[02:18.24]The bone loss happens because bones that usually carry weight on Earth
[02:23.60]do not carry weight in space.
[02:26.69]Space agencies are going to need to make better exercise
[02:31.23]and eating plans to help prevent bone loss, Gabel explained.
[02:36.55]She noted that "During spaceflight, fine bone structures thin,
[02:41.53]and eventually some of the bone rods disconnect from one another."
[02:46.21]The result, Gabel said, is that "once the astronaut comes back to Earth,
[02:52.23]the remaining bone connections can thicken and strengthen,
[02:55.98]but the ones that disconnected in space can't be rebuilt,
[03:01.17]so the astronaut's overall bone structure permanently changes."
[03:06.14]The study's astronauts flew on the space station in the past seven years.
[03:12.79]The astronauts were from the U.S. space agency NASA, Canadian Space Agency,
[03:19.60]European Space Agency and Japan Aerospace Exploration Agency.
[03:25.92]The effects of space travel on the human body
[03:29.56]are important for space agencies as they plan new explorations.
[03:35.35]NASA is aiming to send astronauts back to the moon,
[03:39.26]a mission now planned for 2025 at the earliest.
[03:44.19]Future astronaut missions to Mars
[03:47.26]or a long-term presence on the Moon's surface are also possibilities.
[03:53.47]Gabel said that muscle loss, bone loss, effects on the cardiovascular system,
[03:59.89]and even radiation are big concerns for astronauts.
[04:04.61]"Without gravity pulling blood towards our feet,
[04:08.58]astronauts experience a fluid shift that causes more blood to pool in the upper body.
[04:15.15]This can affect the cardiovascular system and vision," Gabel explained.
[04:21.40]She added that "Radiation is also a large health concern for astronauts
[04:27.01]as the further they travel from Earth
[04:30.22]the greater exposure to the sun's radiation and increased cancer risk."
[04:35.85]The study showed that longer space missions resulted both in more bone loss
[04:42.17]and a lower likelihood of recovering bone later.
[04:46.10]In-flight exercise, such as resistance training,
[04:50.70]proved important for preventing muscle and bone loss.
[04:54.92]Astronauts who performed more deadlifts compared to what they usually did on Earth
[05:01.40]were found to be more likely to recover bone after the mission.
[05:06.31]Gabel said there is still much to be learned about the effects
[05:10.92]of space travel on human health – particularly on space missions longer than six months.
[05:17.79]I'm John Russell. 更多听力请访问21VOA.COM
END OF TRACK. "END OF TRACK." The two men bowed. "Whoever was that person you were talking to?" she enquired, as soon as they stood together. The took of triumph faded from her eyes, she had grown worn and weary. The roses were wilting on the walls, the lights were mostly down now. Hetty, looking in to see if anything was wanted, found herself driven away almost fiercely. I only saw Master Jervie once when he called at tea time, The year 1747 was opened by measures of restriction. The House of Lords, offended at the publication of the proceedings of the trial of Lord Lovat, summoned the parties to their bar, committed them to prison, and refused to liberate them till they had pledged themselves not to repeat the offence, and had paid very heavy fees. The consequence of this was that the transactions of the Peers were almost entirely suppressed for nearly thirty years from this time, and we draw our knowledge of them chiefly from notes taken by Horace Walpole and Lord Chancellor Hardwicke. What is still more remarkable, the reports of the House of Commons, being taken by stealth, and on the merest sufferance, are of the most meagre kind, sometimes altogether wanting, and the speeches are given uniformly under fictitious names; for to have attributed to Pitt or Pelham their[112] speeches by name would have brought down on the printers the summary vengeance of the House. Many of the members complained bitterly of this breach of the privileges of Parliament, and of "being put into print by low fellows"; but Pelham had the sense to tolerate them, saying, "Let them alone; they make better speeches for us than we can make for ourselves." Altogether, the House of Commons exhibited the most deplorable aspect that can be conceived. The Ministry had pursued Walpole's system of buying up opponents by place, or pension, or secret service money, till there was no life left in the House. Ministers passed their measures without troubling themselves to say much in their behalf; and the opposition dwindled to Sir John Hinde Cotton, now dismissed from office, and a feeble remnant of Jacobites raised but miserable resistance. In vain the Prince of Wales and the secret instigations of Bolingbroke and Doddington stimulated the spirit of discontent; both Houses had degenerated into most silent and insignificant arenas of very commonplace business. "It certainly will be. Miss Widgeon," answered Maria, with strictly "company manners." "One who has never had a brother exposed to the constant dangers of army life can hardly understand how glad we all feel to have Si snatched from the very jaws of death and brung back to us." "Just plug at 'em as you would at a crow, and then go on your way whistlin'?" persisted Harry. "Hurroo!" echoed Hennessey; "that's the ticket." "Come forward, keeper," continued the baron, "and state how these arrows came into your hands!" "Yes." HoMEJULIA京香2018下载
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